I don't think my final runnings have ever been that low. But, in general I agree with the theory. That does assume, however, that the gravity of the final runnings is an indicator of a rising pH. As long as the pH stays in range, it shouldn't matter what the gravity of the runnings is, should it?

That's my understanding, Denny. I also wonder how much tannin extraction is an issue with batch sparging. I just don't know how much flavor you can get into wort that's only in contact for 5-10 minutes. (Good or bad; no-sparge beers definitely have more malt flavors per gravity unit, IME.)

Currently a piece of wood serves to tilt my tun towards the braid. Not an agressive tilt. Besides the Coleman Extreme has less than a cup of dead-space.

Once the wort has cleared there isn't a problem with clarity or husks all the way to the end of the lauter.

Concerning what'll continue to dribble out afterwards, bound-up and seeping from the grain bed I no longer worry about. Best to plan one's volumes of wort accordingly and compensate with the sparge or mash water.

Logged

The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

The relation between gravity and pH is such that the alkalinity of the water plays a big role. It provides the counterweight to the acidity of the wort. The more extract you have in water (i.e. the more gravity) the more it will determine the pH. With alkalinine sparge water the bicarbonate of the water will aims at raising the pH. The more there is and the lower the extract content the higher the pH will rise. This also means that in the absence of alkalinity, or very low alkalinity, the pH will change only little as the wort gets more dilute. I have seen the pH rise as much as 0.4-0.5 points in batch sparging. But this only happened with alkaline sparge water and when I either did 2 sparge batches or made a small beer.

I have seen the pH rise as much as 0.4-0.5 points in batch sparging. But this only happened with alkaline sparge water and when I either did 2 sparge batches or made a small beer.

Kai

Which likely explains why I haven't seen it rise. I don't have alkaline sparge water, I almost never do more than one sparge addition, and I almost never make a beer below 1.055. It's good to have data that contradicts my specific situation so that I know it's possible for the pH to rise.

I typically use the last of the runnings for starter wort, so tannin extraction is not an issue for me. Although I probably wouldn't experience that because most of my beers are >1.050. If tannin extraction is a concern for some then I suppose it would beneficial to monitor the wort by checking the sugar level and pH.

I just started to measure last runnings pH.On my 4 SRM Blond Ale (1048) I added Lactic Acid and last running pH was the same as mash pH.In two 18 SRM beers (1069 both) I did not add lactic acid and my pH went up 0.5 and 0.3 points.

I understand that this is relevant to my brewing water.I will be watching last runnings but as of now I would say I should acidify my sparge water. My Alkalinity (CaCO3 ppm) is 91.